How to Wire RCA Cables From a Head Unit to Two Amps

RCA connections from an aftermarket car stereo provide an efficient means of transmitting the music from the stereo-unit signal to external amplifiers. High-quality RCA cables will ensure adequate signal strength as well as noise reduction. Certain high-end car stereos provide several RCA outputs that split the audio signal using an onboard crossover. Multiple RCA outputs from the car stereo allow easy connection options when dealing with two or more amplifiers. Certain amplifiers also feature RCA outputs for connecting an additional amplifier.

Things You'll Need

RCA cable(s)

Basic tool set

RCA splitter

Purchase two sets of high-quality RCA interconnect cables. If the car stereo has more than one set of RCA outputs, purchase two sets of RCA cables that are long enough to connect between both amplifier and car stereo. Car stereos with only one set of RCA outputs only require a long set of RCA cables that reach from the stereo to the amplifiers and a short pair that reach from amplifier to amplifier. Amplifiers that do not have RCA outputs will require the use of a RCA Y-adapter/splitter and two short pairs of RCA interconnects in addition to a longer pair that will run to the car stereo.

Disconnect the vehicle's negative battery cable to avoid electrical shorts and remove the car stereo. Route the RCA cable or cables from the car-stereo-mount opening underneath the dashboard, carpet and trim to the location of the amplifiers.

Tuck the RCA cables as well as the car stereo wiring out of the way to avoid reinstallation problems or damage. Connect the RCA cables to the RCA audio outputs of the car stereo and reinstall the head unit to its original mounting location.

Connect each RCA cable set to the proper amplifier. In cases where only one RCA cable is routed from the car stereo to the amplifiers, connect the RCA Y-adapter or splitter to the single cable leading from the car stereo and then connect the two shorter pairs to both the Y-adapter or splitter and amplifiers.

Reconnect the vehicle's negative battery cable, start the vehicle and turn on the stereo system. Perform gain control and crossover adjustments on both amplifiers according to manufacturer guidelines.

Tips & Warnings

Mark RCA cable connections (leading from the car stereo) used for the front, rear or subwoofer speaker amplifiers with a marker or piece of tape on the cable ends to avoid improper connections to the amplifiers.

Make sure the gain controls on both amplifiers are initially set to "Min" or "0" before operating the stereo for the first time after the installation. This will avoid possible damage to both the speakers and amplifiers before the installer is able to adjust the gain as well as the crossover controls properly.